Filtration process and apparatus



; Sept.30, 1930. 3,1: CABRERA Q 1,776,883

FILTRATION PROCESS AND APPARATUS Filed June'l, 1928 2 Sheets-Sheet 1INVENTOR v MTW m: ATTORNEYS Sept. 30, 1930. c. T. CABRIERA 1,776,883

FILTRATION PROCESS AND APPARATUS INVENTOR BY PM} *W HIS ATTORNEYSPatented Sept. 1 .30 l

" p f I cHARLEs '1': CABRERA, ee NEW Yoax'y ixt Yifnssmnoitmo can;

PoRArIoN," or" new Your; any i; nonronerronlon nnwttoitx 1 a "j m sakeru e 19282.1 ismaiimnaezpiez;

This invention relates to the filtration of solid 1 laden. liquids, andmore particularly concerns, filtration apparatus for j clarifying.

vmust be subjectedto various forms-oftRatment for the removalotsolubleand insoluble solidstherefrom. It is often desirable or cssentiahparticularly in thetreatmentof sews age, that very largequantities of the solid laden liquid be continuously filtered and it isfurther desirable that. substantially all. of

.4 the. soluble or colloidal solids as Wellasinsoluble solids be removedduring the filtering process. The clarification treatments ordinarilyemployed H through mesh screens filter cloths felteel Q: fabrics or bedsof sand andeartlie. These treatments have provenunsatisfactory aforvarious reasons; If mesh screens 1OI',;IE3JbI1O filters are employed,the solubleor.v colloidal; solids are not, removed to. a sufficientezgtent; 1 and due to; thefixed nature 0t the'iinterstices of this typeof filtering medium the insoluble solids quickly clogthe filter andfthuscause an 7 undesirable reduction in the rate: of flow;

of the solid laderr liquidtherethnough, Filter beds ofv sand orwearthiclog quickly, occupy considerable space a and areopen to further seriousobjection in that the flowof liquid therethroughi separates theconstituent, particles thereof andthereby reduces the filtering action.Further, the cleaning of filter beds of granular material" is, adifllcult and expensive operation. i a

ln accorodanceg with the v vention set forth in my copendingapplicaiioni Serial-N 1233;.- cat, filed November 15; 1927,, (pf/whichthis application is a rcontinuation ine par-t, an improved, filteringmediumlis tproyided which overcomes the above described and other difficulties encountered in the fusev of; know-n typeszof filters.Thisimprovedfiltering me:

dium comprises generally amass-of intimate- 1y associatedandclosdy,compacted metallic strandsor filaments. v Initl-ie use of aifilteringmediui'nloflthistype, it has'beeni foundi desirable toprovidespecialrmeans for supporting include o I filtration :eiaat ew,emanates; 8511s 5 laden-{liquid therethrqugh, removing the filteredsolids andcleaning the filtereclgbedsri Itlis; anobjectort;thepresent invention to provide improvedqfiltrationapparatus inwhichfiltering mediumsof metallic W001: and

various other materials maybe advantageous ly employed. Morespecifically it proposed in accordance with the present invention toprovide filtering apparatuspof the gpavity type embed-lying novelremovable-containers for supporting. the filtering;medi m; thesecontainers incorporating convenientmeans for cleansing and replacing thefilteizjngme dium Without handling the mediunainmrrcpnned form. The nntiwi r wn m+ plates the provision of improned: means; for maintainingthe filtering. medium at, the required density Within the containers,.means for supporting the containersandmeans fon 1 confining the flow01: solid laden liguiditovthe filtering-mediumfprioper. I V h Variousother specific 1 objects, advantages and characteristicfeaturesvofthepresent invention-'Will be P'QllltGdBOlit-OIL willbeoome 1apparent as the description. thereof pro,-

gresses. i

I ;In describingthe inventioniinedetail neffi I erence will be made to'the accompanying drawing, in which Figure 1' is a sectional side viewofa filterwing device'constructed accordance-with the present inventionsv l Fig. 2 isa; planview joif; thedevice iwithicer tainpartsthereotremovedq and a a Fig.3, is an enlarged sectional sideview ofone-,ot the filterbecl; containersiof thepresti'n i m oge h With he uept s means-therefor- Thefiltrationapparatusishoivnin thedratv ings and}described heneinlcomprises onezpan ticulan iormotmeans Iincorpona'tingJhe tea times or} the present invention, butr-itshould beu idersto od'that the inventibn is notlimited in its scope 'to theparticularembodiment-dis closed, but isv applicable to a great varietyof uariously: constructed filtration devicesil;

The: filter-ingdevice. shown ncnnprises, gen;- erally a tanlnor, vat Tpreferably oif square or. rectangular shape and? having a-v down 0 'endthereof, extending between the side walls 3 and spacedfrom the bottomwall 1 as shown. Thepartition 2 divides the tank into an inflict passageL and a filter well or passageway I 11V. A suitable inlet trough or openconduit A is fixed to the upper edge of the tankT-at one end thereof incommunication with the upper end of the inlet passage L. 'Thistroughpreferably extends across the entire end of the tank T, as shown inFig.2, A plurality of elongated outlet openings or slots 6 are providednear the upper edges of the side walls 3 and the end wall 7 of the tankT around the filter well TV thereof as shown in Fig. 1, and a gutter 8is fixed to the outer surfaces of the tank walls under the openings 6for the reception of the filtered liquid therefrom. A chute 9 isprovided in communication with the gutter 8 for carrying away thefiltered liquid.

The tank T as well as the partition 2, the trough 4 and the gutters 8may be formed of wood, metal or any other suitable material, thematerials employed being preferably unefl'ected by the liquids to betreated. The tank T may be supported in any suitable manner,asforexample, by the corner posts or columns 10.

The lower apex of the bottom wall 1 of the tank T is connected through acut-off valve 11 to an ejector E of suitable construction. The ejectoris provided with an outlet pipe 12 having a cut-off valve 13 therein.The par ticular construction of ejector used forms no part of thepresent invention and therefore will not be described herein, it beingsufficent to understand that this device operates, with the aid ofcompressed air or otherwise, to carry the accumulated sludge or sedimentaway from the bottom of the tank T.

Referring now more particularly to the construction of the filter bedcontainer and the supporting means therefor, which comp'rise importantfeatures of the present invention, the filtering medium, which in theillustrated embodiment comprises metallic wool, is retained within oneor more openended containers C which are supported within the filteringwell W of the tank T as shown in Fig. 1. Each container 0 comprisesgenerally an open-ended rectangular or square shell composed of twointerconnected and separable sections 1 1 and 15. The upper section 14:is preferably of substantially greater depth than the lower section 15and is provided with awide continuous flange 16 extending outwardly atright angles to the walls thereof at their upper edges as shown in Fig.3. A continuous inwardly extending flange 17 is provided around thelower edges of the walls of the container section 1 1, the flanges 16and 17 being preferably formed as integral parts of the section. A wiremesh screen or other suitable permeable partition 18 is supported acrossthe lower open end of the section 14, being carried on and reinforced bya plurality of cross bars 19 of metal or other suitable material, theends of the bars 19 being supported by the inturned flange 17.

Thelower section 15 of the container C is provided with continuousinwardly extending-flanges 20 and 21 at the upper and lower edgesthereof respectively, these flanges being preferably integral with thewalls of the section. A screen or permeable partition 22, similar to thescreen 18 of the upper section, is supported across the lower open endof the lower section 15 by a plurality of bars 23 resting onthe lowerinturned flange 21 as shown.

. The 'two sections 14 and 15 are preferably interconnected by suitablemeans providing a liquid-tight seal. In the embodiment shown, suitableangle brackets or angle irons 24 are secured to the outer surfaces ofthe walls of the upper section 14. at their lower edges, andcorresponding brackets 25 are similarly fixed to the walls of the lowersection 15 at their upper edges. A gasket 26of rubber or other suitableresilient and impervious material is inserted between the flanges 17 and20 of the sections 14 and 15 respectively, and the sections are clampedtogether by means of bolts 27 or other suitable fastening means engagingthe brackets 24 and 25.

The filtering medium employed is packed within the container sections14: and 15. This medium preferably comprises metallic wool of the typedescribed in my copending application Serial No. 233,497, filed November15, 1927, and Serial No. 282,217, filed June 1, 1928. In general, it ispreferred to employ a wool formed of a plurality of intermixed andintimately associated strands of physically and potentially dissimilarmetals such as leadand zinc for this purpose, but it should beunderstood that the invention is not limit ed to the use of any specificfiltering medium. When metallic strands or filaments are employed as thefiltering medium, it is preferred that the metals used be so chosen thatthe intermixed wool is resilient to a certain degree and also hassuflicient mass and body to withstand the rapidflow of solid ladenliquid therethrough without undue displacement or separation.

The filtering medium 28 is packed within the lower section 15 of eachcontainer C against the screen 22 therein, being compacted to therequired density by means of suitable pressing apparatus or by the useof hammer blows, if necessary. A quantity of the filtering medium 28 issimilarly packed within the upper section 14 on the screen 18 thereof.The filtering medium in the upper section 14 of each container 0 ispreferably maintained at the required density by a suitable retainingpress which is shown in detail in Fig. 3. A screen or other permeablepartition 29- isplaced over the filtering -mfe- -dium 28,;andbarrectangularframe 30 having cross members, 31" isplalced' over thisscreen. suitablescrew 32 having an ogp- :erating wheel;33 fixedto theupper-end there'- of is journal'edy in, an opening atgthercenter f theframe 30, and threadedly engages an openingfina cross b'race'i84, Thebrace 84 is], preferably formed with a plurality of container section;14

radiallyrextending arms which are retained *beneathlia plurality ofinwardly 'cext'ending I iangle braokets 35, suitably secured to theupper edges of the walls oftheseetion 14. By advancing the screw 32through the brace 34, the frame SOand the screen 29 arepressed angle,about the screw as an axis thereby moving the arms of the brace fromunder the "brackets, 35,. and permitting the 1 with? drawalfoftheib'race 34, the frame and the screen 29 from the upper open end ofthe A pair of oppositely disposed inwardly extending angle brackets 36are preferably provided at theupper edge of the container 1 sectionsF141 for use in lifting thecontainerC openings in the side walls oftheupper sec-' or. the upper section thereof; out of; the tank T, ashereinafter more fully explained;-

Eachlof the containers 1C is preferably provided with a pluralityofspaced-cleaning tion, '14 'thereof. These opening'sfare norlnallyclosed by suitable meansrsuch. as the covers '46, which may be hingedto} the container walls-and held intheir closed positions by suitableclamps 47. :Resilient gaskets48 are preferably employed in connectionwith the covers 46, to insure a; liquid-tight closure.

f The containers G, are "preferably removably l secured jwithin thefiltering weu W of the tank T, in such a: manner that the solid ladenliquid is forced to flow upwardly therethrough, i In the embodimentshown, the container support comprisesfla pluralityiof in-v terconnectedor integral horizontal plates or ledges extending across, the filteringwell W at a point below tthe normal. liquid1-level therein, as shown.Thesesupporting plates preferably take the form of a single metallicframe 37 having a plurality of rectangular openings '38- for: thereception of the container Q. As shown: in, Figs, 2 and 3', the

openings 38 are larger than the containers G but smaller thanthe outsidedimensions of the outwardly extending flanges 16 at the upper edges ofthe containers. 1 The containers C are lowered through theiopenings 38and supported byJthe; engagement of. the

flanges 16 withithe frame 37. A liquid-tight joint between the flanges;16 and frame -371 tainer is obtained by the use of suitable resilientgasket 49 and the flanges 16 "arelpreferably clamped to. the frame, 37bysuitable bolts 39gandnuts 40., Thernuts4O arepprefenably welded orotherwise suitably secured, t0 the lowersur faoe of the frame 37topr'event; their loss and toi f'acilitate the removal and replacementofthewbolts1-39. The f'rame37 may be provided; withany suitable numberof openings, thenumber so chosen: being dependent upon the size of theindividual containers C and the rate of flow 10f liquid to be .han dled;7

' One or morezconveyor bracketsxor beams v .41; are provided abovethetank I, each'of 'these brackets being disposed) to pass directlyfoverthe center ofone or more oflthe 'c-ontainers G. A suitable support42 is1novably mounted on the bracket '4Ibyrollersor other means, and one endof a liftingtackle g .43 of'anytknowntype is seoured toftl1is;sup-

port, A cross bar 44 is secured at its mid 'pointtot-helower end'oftheliftingtackle V 43, this bar'bei-ng of a suitable'length toipass withinthe conta inersC and engage-the lower faces of the oppositelydisposedbrackets 36 of the containers. It will be apparent that bymoving; thesupport 42 to a position dii rectly -rabove thecen-te'r of. a containerand engaging the bar 44 beneath, the 'brackets 36 the container may belifted out'kofthe conpoint; i

. The operation oflthe filtratibnapparatus of; the presentinvention'will now be described. The filter bed, containers C'arefilledwith metallic wool or'any othersuitable filtering medium, the lowersections 15rof the con.- tainersfibeing packed to the requiredidensityand clamped to. the upper sections 14, and

the material in Lthe uppensections being pressed tolthrequired'densitybythe screws 32 'andthe. frames 30. The containers C are7 then "bolted into the-openings 38in the frame 37 of the filter well Nand the apparatus is then "ready *foruse.

The solid'ladenliquid introduced tothe inlet chamber Lfth'rough thetrough 0r conduit 4 and this liquid-flows downwardly under the loweredges ofthe partition 2 and then upwardly into theWeIl l/V and through ithe; several-filter bed containers C. Because *of the liquid-tightjoints between the con- :tainer' sections andbetween the upper edges'ofthe containers and the frame 37, all-of the liquid is forced. tortravel through: the filter ;beds;within the containers. Whenlthe solidfladen liquid; is firstiintroduced to the tank T,

the' valve 18 "isi closed' and the valve 11 is -opened, -and'theinsoluble solids as well as the soluble or colloidal solids filtered:"from the liquid: vehicle by the 5 filterbeds settle to,

the lowerapexpff the tank T and ifill the ejector E; After the sludgethus-filtered from the liquid :hasreac hed' a level iconsiderably as I,.an d transported to. any*desired v above the lower apex ofthe tank T,the valve 11'is closed, the Valve 13 is opened, and the ejector isoperated to remove the sludge therefrom through the pipe 12. Since thesludge is permitted to build up to considerable depth within the tank Tbefore the ejector E is operated, the sludge within the ejector iscompressed to a considerable extent by the weight of the column ofsludge within the tank, and a considerable quantity of liquid is therebyextracted from each charge of sludge before it leaves the ejector. Theejecting operation is repeated at suitable intervals as the filtrationprocess continues.

The wide and shallow nature of the inlet trough 4 permits theintroduction of the solid laden liquid to the tank T at a comparativelyhigh rate without unduly agitating or stirring the liquid within thetank. This feature is of considerable importance in connection with thebuilding up of a column of sludge at the bottom of the tank just priorto each operation of the ejector E as explained above.

The hydraulic head required to force the solid laden liquid through thefilter beds is maintained by the liquid column in the inlet passage L,it being readily apparent from the disclosure of Fig. 1 that this liquidcolumn is considerably higher than the normal liquid level within thefilter well W. The filtered liquid rises from the filter beds andfiowsoutof the filterwell through the opening or slots 6 near the upperedges of the side walls thereof, this liquid being caught in the gutters8 and conducted away through the trough or chute 9. If desired, thefiltered liquid may be further clarified by. passing it through a secondfiltering device substantially identical with the filtering devicedescribed. When this further filtration of the liquid is required, theoutlet trough 9 of the tank T is arranged to communicate directly withthe inlet trough of another tank, not shown, and the liquid is treatedin such second tank in the manner described above.

During the filtration process, a certain amount of sludge and sedimentcollects in the filtering medium within the containers C and it istherefore desirable to periodically clean the filter beds. WVith theapparatus of the present invention, the lower portion of each filter bedis supported in a separable section 15 of the container C, which sectionmay be removed and cleaned without cleaning the entire depth of the bed.

When it is desired to clean or replace the lower portion of the filterbeds, each container C is separately subjected to the followingoperation. The bolts 39 are removed from the flange 16 of the container,the, screw 32 is loosened and the brace 34 is removed from the upper endof the upper container section 14. The lifting bar 44 is then engagedbeneath the brackets 36 of the container, and the entirecontainerislifted from the frame 37 to a poby pas'singhot water, steamor dilute acid 'therethrough. It is usually preferred to keep aplurality of extra lower sections 15 clean and ready for use, so thatone of these clean sections may be immediately connected to the uppersection and the complete container C returned to its operating positionin a minimum time. The clean lower section 15 is placed on thesupporting bars 50, the upper section 14 is lowered into engagement withthe lower section and the two sections are bolted together as describedabove to form a complete container 0; The container is then lifted a fewinches, the bars 50 are removed and the container is lowered into placeand clamped to the frame 37 as described above. The brace 34 and screw32 are then replaced within the upper end of the upper section 14, andthe filtering-medium is compressed to the desired density, after whichthe apparatus is in condition for use.

After extended periods of continuous use, it is desirable to cleanse theupper portions of the filter beds supported within the upper containersections 14. This is conveniently accomplished by separately removingeach container C and disconnecting the lower section 15 thereof in themanner described above. Each upper section 14 is then transferred by themoving of support 42, running on the track 41, to some convenient point,and is placed within a washing tray or other suitable liquid receptacle,not shown. The covers 46 are then removed from the openings 45 in theside walls of the section. Streams or jets of hot water, steam, diluteacid or any other suitable cleaning fluid are directed into thefiltering medium 28 by means of pipes or hoses inserted through theopenings 45. Due to the fact that the openings 45 are distributed overvarious portions of the container section walls, and lie at differentlevels in the section, the entire mass of filtering material may bereadily loosened up and washed clean in this manner. After beingthoroughly cleansed, each upper section 14 is returned to the tank T,secured to a clean lower section 15 and replaced in the frame 37 asexplained above.

It is entirely feasible, and sometimes desirable, to employ an extra setof upper container sections 14 as well as lower sections 15 and to cleaneach set of upper sections while the otherset is in use. This procedureis advantageous in thatit reduces the time during which the filteringapparatus must be shut down. It should be understood that in mostcommercial filtration plants, at least two com plete filtering devicesof the type described 7 will be employed, and the filter beds of thesedevices will preferably be alternately cleaned or replaced. In thismanner the continuous treatment of the solid laden liquid is insured.

The advantages of the filtering apparatus of the present invention arereadilv apparent.

Due to the construction and arrangement of the filtering mediumcontainers and the supporting means therefor,'all of the solid ladenliquid is forced to flow through the filter beds. The capacity of thefiltration apparatus may be 'varied'by increasing or decreasing thenumber of filtering containers employed, the unoccupied openings in theframe 37 be- 1ng closed by suitable liquid-tight covers.

, The containers C comprise convenient means for handling and supportingthe filtering medium, and since comparatively large quantities of thismaterial are employed in filters of r the present type, the manner inwhich the medium is supported,cleanedand replaced is of considerableimportance. The filter bed containers include adjustable and removablemeans for compressing the filtering medium to the required density andmaintaining the medium in this state throughout the opera tion of thedevic'e. Due to the simplicity of construction and the,interchangeability of the filter bed containers,..the cleaning andreplacement of the filtering medium maybe accomplished with a minimumexpenditure of time. and labor.

I claim 1. In a device for filtering solid ladenl liquids, a passageway,means for directing a stream of liquid through said passageway, at aleast one open ended container removably secured across said passagewayin the path of said liquid stream, and a mass of filtering materialsupported within I said container, said container having a plurality ofnormally.

closed openings in the sidewalls thereof to permit the introduction of acleaningfiuid to said filteringmaterial. v 2. A filter bed comprising acontainer hav-.

ing open ends, a permeable partition secured across the lower end ofsaid container,amass of filtering material within saidcontainersupported by said partition, and means removably secured to the upperedge of, said container for compressing said filtering material tothepdesired density, said container, I

having a plurality of openings in the side walls thereof to permit theintroduction of a i cleaning 'fluid to said filtering material.

3. In a device for filtering solid laden liquids,a passageway, means fordirecting a stream of liquid through said passageway, a"

filter bed supportedin said passageway comprising a plurality of openended container sections detachably connected in end-to-end relation, apermeable partition secured across the lower open end of each of saidsections,

masses of filtering material supported on said partitions within saidcontainers, and means detachably'secured to the upper end of theuppermost container section'for compressing said filtering material tothe required density.

4. In a device for filtering solid ladenliquids, a tank, a verticalfiltering passageway in said tank, means for directing a stream of solidladen liquid upwardly through said passageway, aframe extending acrosssaid passageway havinga pluralityof 0 g openings therein, an open endedcontainer 'removably secured in each of said openings,

amass of finely stranded metal in each of said bodily from the filteringcontainer, removing from the filter bed the-layer offiltering ma- 5terial with which the liquid to be filtered first comes intocontact,'replacing said layer with a clean layer of filteringmateri'aland replacing the entire filter bed bodily in thefiltering container. vIn testimon whereof I affix my. signature. VEHARLE S T. CABRERA.

